Remember to use 3.3V as source for the ADF4351 module (pin 7 vcc and pin 5 as GND)and a voltage divider for signals: If you are using a 3.3V microcontroller like for example Arduino DUE, or Teensy ...

This library supports the ADF4351 from Analog Devices on Arduinos. The chip is a wideband (34.375 MHz to 4.4 GHz) Phase-Locked Loop (PLL) and Voltage Controlled Oscillator (VCO), covering a very wide ...